The increasing exposure of human populations to cadmium in the environment and workplace has necessitated the development of biological/chemical warning signs of human exposure to his toxic heavy metal. The long-term goal of this research is to develop a reliable biomarker or set of biomarkers that could serve as a quantitative reflection of the extent of human exposure to cadmium in the environment, workplace, and home. The specific aims of th project are (a) to study the excretion patterns of urinary cadmium and metallothioneins i animals exposed to cadmium on a chronic basis; (b) to investigate the excretion patterns of the urinary lipid metabolites--formaldehyde, acetaldehyde, malondialdehyde, and acetone; and (c) to carry out a thorough correction analysis aimed at establishing links, if any, between urinary cadmium, metallothionein and the lipid metabolites and the body's burden of cadmium. Three population of Sprague-Dawley rat, comprising 200 ra ts each, will be used. Each population will be exposed to Cd via drinking water for upwards of 24 weeks. The first population of rats will be used to study urinary and liver/kidney Cd, the second population will be used to study urinary and liver/kidney metallothionein while the third groups is used to study the excretion of urinary lipid metabolites. Each population is further divided into four groups of 50 rats each. Three groups will receive Cd via drinking water at doses of 5 mg/L, 25mg/L and 125 mg/L, while the fourth groups, serving as control, receives deionized drinking water. The three populations of rats will be used to gather data on liver/kidney and urinary cadmium; liver/kidney and urinary metallotheionein and urinary lipid metabolites. Although the maximum length of exposure shall be 24 weeks, animals will be removed every 4 weeks fur urine and then kidneys and liver, upon sacrifice. Extensive statistical, regression and correlation analysis of Cd, MT, and lipid metabolites data from these studies will help to establish the viability of using any or all of these urinary metabolites as a biomarker of human exposure to cadmium in the environment, home and workplace.